Spectroscopic characterization of an atmospheric pressure dbd afterglow under unipolar and bipolar pulsed excitation

International audienceThis experimental work deals with the study via spectroscopic diagnostics of the afterglow issued from an atmospheric pressure Dielectric Barrier Discharge (DBD) reactor driven by two distinct High Voltage (HV) generators. The first High Voltage generator delivers unipolar (positive) square pulses of variable rise/fall time, frequency, amplitude and pulse duration. The second one delivers bipolar HV pulses of variable frequency and amplitude. After a primary electrical analysis of the behavior of the two systems, attention is drawn in the production of active species in the case of N2 and Air DBD's in the afterglow. The aforementioned species' densities are estimated in these experimental conditions via optical emission spectroscopy for the N2 afterglow, whereas the well known absorption method is used in the case of the Air afterglow.It is shown that the unipolar mode of excitation is more efficient in the production of ozone whereas the bipolar one excels in the production of atomic Nitrogen and N2(A) metastables. These species can be used in a wide variety of surface and gas treatment applications in atmospheric pressure conditions